The Charter does not, however, establish at what point differences in expression result in a separate language, deeming it an "often controversial issue", and citing the necessity to take into account, other than purely linguistic criteria, also "psychological, sociological and political considerations".[7]

Although the original Italian Constitution does not explicitly express that Italian is the official national language, it could be implied because Italian is the language the constitution is written in. Since the constitution was penned, there have been some laws and articles written on the procedures of criminal cases passed that explicitly state that Italian should be used:

Aosta Valley: French is co-official (enjoying the same dignity and standing of Italian) in the whole region (Le Statut spécial de la Vallée d'Aoste, Title VIe, Article 38);[10]German is unofficial but recognised in the Lys Valley (Lystal) (Le Statut spécial de la Vallée d'Aoste, Title VIe, Art. 40 - bis).[10]

Trentino-Alto Adige/Südtirol: German is co-official (enjoying the same dignity and standing of Italian) in the province of South Tyrol (Statuto speciale per il Trentino-Alto Adige, Titolo XI, Articolo 99);[18]Ladin, Cimbrian and Mòcheno are unofficial but recognised in their respective territories (Statuto speciale per il Trentino-Alto Adige, Titolo XI, Articolo 102).[18]

According to the UNESCO's Atlas of the World's Languages in Danger, there are 31 endangered languages in Italy.[20] The degree of endangerment is classified in different categories ranging from 'safe' (safe languages are not included in the atlas) to 'extinct' (when there are no speakers left).[21]

The source for the languages' distribution is the Atlas of the World's Languages in Danger[20] unless otherwise stated, and refers to Italy exclusively.

All living languages indigenous to Italy are part of the Indo-European language family. The source is the SIL's Ethnologue unless otherwise stated.[23] Language classification can be a controversial issue, when a classification is contested by academic sources, this is reported in the 'notes' column.

Sardinian is a distinct language with significant phonological differences among its dialects. Ethnologue, not without controversy, even considers Sardinian as four independent languages, which are included in a hypothetical subgroup named Southern Romance, along with Corsican.[24] Gallurese and Sassarese are considered dialects of Corsican by UNESCO,[20] rather than being Sardinian varieties.

Any such classification runs into the basic problem that there is a dialect continuum throughout northern Italy, with a continuous transition of spoken dialects between e.g. Venetian and Ladin, or Venetian and Emilio-Romagnolo (usually considered Gallo-Italian).

All of these languages are considered innovative relative to the Romance languages as a whole, with some of the Gallo-Italian languages having phonological changes nearly as extreme as standard French (usually considered the most innovative of the Romance languages). This distinguishes them significantly from standard Italian, which is extremely conservative in its phonology (and notably conservative in its morphology).